In camera ND filters
 

So along the lines of my 20 questions of the week theme..

The strength of the ND filters in the camera are described as 1/6 and 1/32.

How many stops are they each? I can't figure it out. I am trying to place an order for ND Grads and a couple of ND filters to have a little more control of light.

Thanks,
Jay

You definitely need more external ND; in bright sunlight even with ND2 on I found it overexposing.

1/6 = 2.5 stops
1/32 = 5 stops

Hardly ever do I disagree with Barry, but I could have sworn that ND 1/6 is equal to two and two-thirds stops... anybody? Fully agree with ND 1/32 equaling five stops, of course.

Okay, according to Canon USA, they're calling it two and a half stops for ND 1/6,
see http://www.usa.canon.com/app/html/XL...n_optics.shtml (written for
the XL H1 stock 20x lens but applies also to the XH series camcorders).

DOH! Yes, two and one half, not one and one half. Sorry, blew it on the math. 1 stop = 1/2, two stops = 1/4, 3 stops = 1/8, 4 stops = 1/16, 5 stops = 1/32. So 1/6 = halfway between two and three stops, hence 1/6 = two and one half stops.

First post edited to avoid anyone seeing it and thinking the original post was accurate.

Thankyou, it seemed to be a large split. So a full set of ND's is in order. Does anyone have an opinion on "White Water glass"?Are the filters labled "HD" really better than the high end glass from proffesional photograghy?

The Canon FS72 filter set includes an ND8, which should be pretty versitile along with the built-in ND filters.

Personally I like a set of slide-in ND grads with a lightweight lens hood like the Formatte.

If you go for the Cokin Pro Z resin filters they're cheaper and more lightweight than glass filters. And although they're not a scratch resistant as glass, as long as you're careful with them you shouldn't have too much of a problem. And they're cheap enough not to worry too much if they do get scratched.

Well I've got to disagree with Barry as well. To say: 'in bright sunlight even with ND2 on I found it overexposing' suggests that there's a camera fault which of course there isn't. Just operator error, my friend. Said with a smile.

Jay, grads and polarisors are good, but if you can aviod filters altogether so much the better. You can always soak another stop by upping the shutter speed of course. Never stack them either.

Cameras with such tiny chips have tremendous dof, so filters and wide converters have to be kept absolutely spotless and well hooded. And don't believe any tosh you read about 'HD' filters. If you're buying filters with a reputable brand name you'll be fine.

Main thing to say is don't ever use a filter that isn't multi-coated. You'd not buy a G1/Ai if the front element was uncoated, now would you? So don't make it so by using uncoated filters.

tom.

Er... how? Daylight scene, 24F, 1/48 shutter, the iris was closed down to f/9.5, the ND switch was on ND2, and there were still areas blowing out. I had to set it on 1/90 shutter to get it to not blow out. How would that be classified as "operator error"?

Yes you can get it under control, but I don't want the look of the 1/90 shutter. So the only way to get proper exposure (without compromising the desired shutter speed) in that circumstance would be to have an external ND filter, because the in-camera ones aren't quite strong enough.

Ah - now you're telling me you *didn't* get over-exposure because you upped the shutter speed. But originally you'd said:

'in bright sunlight even with ND2 on I found it overexposing'.

But I agree with you - I don't like the stacatto effect of raising the shutter speed above the default, so as you say, external ND is the answer to this one.

tom.

You should be using aperture/ND for exposure, not the shutter. Use the shutter for controlling motion blur and for most who shoot 24P, emulating the 180 degree shutter of a film camera, that means leaving it set to 1/48 as Barry was doing.

I know the shutter indirectly affects exposure, and I tended to use it for exposure when shooting stills. But in that case, you normally want your subject 'frozen' in time and higher shutter speeds are the only way if the movement is fast enough.

Hey Barry, most computer types would instantly recognize that progression of denominators! :-)

-gb-

This always confuses me because I think of ND filters as .3, .6 and .9, etc.

The decimal point numbers in those filter designations refer to 1/3-stop increments. So a .3 would cut the light by three thirds of a stop, or one full stop.

Under that nomenclature, the XHA1's filters would amount to a .75 and a 1.5.

Interesting...after all these years of saying ND.3 and ND.6, etc., I've never known they mean one third of a stop. A .3 is a stop, .6 two stops, etc. Never even thought about where the number itself came from. Learn sumpthin' new every day, don'tcha.